Convergence of Standard and/or High Definition TV (SDTV and HDTV) and personal computer (PC) systems is the new promising category of products for emerging multimedia markets.
In current systems, PC graphics video is generated by PC video subsystems which convert CPU generated commands or digital video data in images on PC monitors. HDTV video is generated from the signal received from video source (satellite, over the air, cable, DVD, Hard Disk, Internet, etc.) by a HDTV video subsystem to generate images on TV screens.
Both HDTV and PC video subsystems have very similar architecture, consisting of a video chip and video memory. While the HDTV and PC video chip each support particular features, they are very similar in overall function.
Currently, HDTV video subsystems comprise a unit known as a Set Top Box (STB) unit which typically contains a microprocessor, memory, MPEG decoding chip, audio decoding and processing components and optionally hard disk, LAN interface, extensive I/O etc. Full-function STB can also run an operating system (usually Linux™ or Windows CE™), and specialized software applications. Such full-function STB devices tend to be complex and expensive specialized HDTV computers, which unfortunately lack the full performance and functionality of regular PC. The trend in the industry is towards using the capabilities of regular PCs for HDTV video subsystems. Indeed, PCs are becoming more and more pervasive in households and are sufficiently powerful to perform many audio and video processing of the level required by an HDTV subsystem.
Prior art PC/HDTV systems do not connect PC video subsystems directly to the set-top box or connect the PC video subsystem to the set-top box subsystem through display cables, such as DVI, which are expensive and unsuitable for use over long distances or for feeding multiple displays. Such display cables used in prior art systems are needed since the video signal is processed and prepared for display on the PC side, where the graphics processing unit (GPU) lies. There exists therefore a need for a PC/HDTV system which would provide the advantages of a remotely located PC without the disadvantages due to directly transporting PC video signals over long distances to the point of display.
Additionally, full-function stand-alone STB units combining HDTV and PC functionality require built-in PC equivalent software and hardware at each remote point of HDTV/PC display which increases significantly the cost of such systems, especially with multiple STB units.